Butterflies at Baskett Slough, Ore.

Witness one of Oregon's rarest—and prettiest—insects at this Willamette Valley wildlife refuge.

The excitement is right at your feet in late May. That’s when Fender’s blue butterﬂies emerge from their cocoons and take ﬂight near Salem, Ore., at Baskett Slough National Wildlife Refuge, home to one of the state’s largest populations of the rare insects. Timing is key: You need a sunny spring day to catch them hatching, says Cheryl Schultz, a conservation biologist at Washington State University–Vancouver.

Once thought extinct, the endangered butterﬂy with stunning iridescent sky-blue wings just an inch across has made a steady comeback at the refuge. Look for ﬂashes of blue near the purple ﬂowers of Kincaid’s lupine, a threatened prairie plant that provides food for the insect as a caterpillar and a place to hide before its brilliant spring debut.

When you’ve seen your ﬁll, climb a path to a view of the area’s shallow wetlands. But tread carefully—you’re in the butterﬂies’ living room. (503) 623-2749, fws.gov/willamettevalley/baskett.[3]